Rail side wear and its effect on train steering properties in curves

Freight wagons running on Finnish tracks can follow either the European TSI-standard or GOST-standard, so there is variation in wheelset dimensions and track clearance nominal values for freight wagons. Therefore, a great amount of attention should be given to the amount of rail side wear, which also affects the track clearance value. The aim of this study is to evaluate suitable rail side wear limits in Finland. The effect of rail side wear regarding train movement in curves has been examined by looking at its effect on the wheel-rail contact points and wheelset rolling radius difference. This has been calculated with a large number of field measurement results on rail profiles with different amounts of side wear. Additionally, some simulations with vehicle models have also been made to estimate wheel-rail contact forces and to predict the risk of derailment. Based on several different worn rail profile calculations, it was revealed that rail wear in curves weakened the wheelset steering properties. In many cases, the value of the wheelset rolling radius difference approached zero in parallel with rail wear, corresponding to very poor wheelset steering properties. This typically points to more flange contacts. However, it did not indicate an increase in the risk of derailment.